Something totally gross is an infected bedsore. Imagine a wardful of spinal cord injured patients and almost all of them with infected bedsores. You could smell it from the door...
I was around someone who had there stiches burst because they'd built up a post surgery anaerobic bacterial infection .. that was a pretty disgusting smell. Actually very disgusting. The kind of smell where you realize that person had been close to death
..that idea and trace sense memories stay with you.
In general though if it's someone's health and welfare at stake, I can tune out most smells and sounds and visuals and concentrate on the emergency. I doubt I ould be a crime scene investgator. But in sad situations, or emergency situations I don't usually get too squicked.
On a site note.. I've been in a morgue and it wasn't gross. It was only a little scary, and didn't smell or anything. The only thing that was gross is that the med students put their lunch bags in the same fridge as some of the specimen jars.. That was a pretty rank concept